Spring Tutorials

The JmsTemplate contains many convenience methods to send a message. There are send methods that specify the destination using a javax.jms.Destination object and those that specify the destination using a string for use in a JNDI lookup.

package r4r.in;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.jms.core.MessageCreator;
public class jmsSender
{
private Destination destination;
private JmsTemplate jmsTemplate;
public jmsSender() {}
public void setJmsTemplate(JmsTemplate jmsTemplate)
{
this.jmsTemplate = jmsTemplate;
}
public void setDestination(Destination destination)
{
this.destination = destination;
}
public void sendMessage()
{
MessageCreator creator = new MessageCreator()
{
public Message createMessage(Session session)
{
TextMessage message = null;
try
{
message = session.createTextMessage();
message.setStringProperty("text", "Hello Spring JMS");
}
catch (JMSException e)
{
e.printStackTrace();
}
return message;
}
};
jmsTemplate.send(destination, creator);
}
}

The jmsSender class needs to be aware of two things, one is the destination object where the message has to be sent and the other being the JMSTemplate object that simplifies the process of sending the message. The sending of the message is defined by the method JMSTemplate.send() that takes 2 arguments.

The first argument is the message destination itself and the second argument is the message creator object that knows how to create a message that can be sent later.

Receiving a message using JMS API

Synchronous Reception: While JMS is typically associated with asynchronous processing, it is possible to consume messages synchronously. The overloaded receive(..) methods provide this functionality. During a synchronous receive, the calling thread blocks until a message becomes available.This can be a dangerous operation since the calling thread can potentially be blocked indefinitely. The property receiveTimeout specifies how long the receiver should wait before giving up waiting for a message.

Asynchronous Reception Message-Driven POJOs: Message-Driven Bean (MDB) in the EJB world, the Message-Driven POJO (MDP) acts as a receiver for JMS messages. The one restriction on an MDP is that it must implement the javax.jms.MessageListener interface.

package r4r.in;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.TextMessage;
import org.springframework.jms.core.JmsTemplate;
public class jmsReceiver
{
private JmsTemplate jmsTemplate;
private Destination destination;
public MessageReceiver() {}
public void setJmsTemplate(JmsTemplate jmsTemplate)
{
this.jmsTemplate = jmsTemplate;
}
public void setDestination(Destination destination)
{
this.destination = destination;
}
public void receiveMessage()
{
Message message = jmsTemplate.receive();
TextMessage textMessage = null;
if (message instanceof TextMessage)
{
textMessage = (TextMessage)message;
try
{
System.out.println(textMessage.getStringProperty("text"));
}
catch (JMSException e)
{
e.printStackTrace();
}
}
}
}